1. Field of the Invention
Embodiments relate to a radio frequency identification (RFID) reader in an RFID system.
2. Description of Related Art
Generally, a radio frequency identification (RFID) system includes an RFID tag for storing information and exchanging data using protocols, and a reader, i.e. an RFID reader for wirelessly communicating with the RFID tag. The RFID tag is classified into an active type that requires power from a power supply and a passive type that operates by an electromagnetic field of the RFID reader without directly receiving power from an internal or external power supply.
The RFID tag may be formed in various types of shapes. Accordingly, the RFID tag may be inserted into a plastic disc, a cylinder, a card, a thin flexible band, a hollow glass bead, and the like. Examples of the RFID tag include a single-bit read-only tag that is used for security, a 32-bit or 64-bit read-only tag with unique codes that can identify each tag, a 512 kb read and write tag that a user can arbitrarily correct contents of a memory, and the like. The RFID tag generally uses frequency bands of 125.134 KHz, 13.56 MHz, 433 MHz, 860 MHz to 960 MHz, or 2.45 GHz.
The RFID reader is also referred to as an interrogator and includes an RF unit that enables communication with the RFID tag using RF energy. The RFID reader may be in a portable form or in a fixed form to receive a signal from the RFID tag and read data included in the signal.
A passive RFID system of an ultra high frequency (UHF) band uses a backscattering scheme and thus, the magnitude of a signal emitted from the RFID reader is significantly greater than the magnitude of a backscattered signal of the RFID tag. Accordingly, in the RFID system, the RFID reader may not correctly recognize the signal of the RFID tag.